Plate glass surfacing table



.April 4, 1939- A. L.. HARRINGTON 2,152,801

PLATE GLASS SURFACING TABLE April 4, 1939. A. 1 HARRINGTO'N 2,152,801

' PLATE GLASS SURFACING TABLE v Filed March 29, 1958 3 sheen-sheet 2- 2.1 I* 4 .18 20` 23 18 a, -l l/u l I?? .15 u /V WLM April 4, 1939. A. L. HARRINGTON 2,152,801

I PLATE GLASS SURFACING TABLE n l Filed March 29, 1938 3 Sheets-Sheet 3 IN1/mma. H1. F/eso L.. HngR//v-ro/v RNEYS.

. mfw? de@ Patented Apr. 4, 1939 U'NiTED STATES PLATE GLASS SURFACING TABLE Alfred L. Harrington, Rosslyn Farms, Pa., assignor te Pittsburgh Plate Glass Company, Al-

legheny County, Pa.,

Sylvania Applicaticn March 29,

7 Claims.

The invention relates to tables for use in surfacing plate glass, in which the tables are passed in a continuous train beneath a series of grinding and polishing runners. 'Ihe heat developed in the polishing operation causes the tops of the tables to Warp or bow slightly, so that they are no longer true and flat, and when returned to the grinding end of the cycle for reuse, this bowed or warped condition persists to a certain extent so that the glass sheets are not ground to uniform thickness, the sheets being ground thinner in the portions overlying the centers of the tables than those overlying the sides of the tables. The object of the present invention is to provide an improved table construction in which the warping of the table tops due to the heat developed in vpolishing is substantially eliminated.

Further objects are to provide a table of the kind specified having a false tcp with a cooling space therebeneath (l) which is relatively free to expand and contract in all directions in its own plane when subject to temperature changes, so that the tendency to warp is reduced to a mini mum, and (2) which is securely anchored against warping throughout its area. Certain embodiments of the invention are illustrated in the accompanying drawings, wherein:

Figure 1 is a plan view of the table. Fig. 2 is a side elevation. Fig. 3 is a transverse section on the line III-III of Fig. 1. Fig. 4 is an enlarged partial section on the line IV-IV of Fig. 1. And Figs. 5 and 6 are views similar to Fig. 4, but showing modications.

Referring to the drawings, I is the body of the table which is provided with the wheels B engaging the rails 8a of the grinding and polishing system. The body of the table includes a top plate 9 stiiened cn its under side by transverse and longitudinal ribs Il! and II. Distributed over the upper surface of the plate 9 are a series of metal strips I2, each ci which is clamped securely in position by a bolt I3 having a head Ill. The upper faces of the heads I4 are machined to the same horizontal plane and constitute supporting means for a false top plate I5. Mounted on each of the strips E2 and vulcanized thereto is a rubber tension block I5. These tension blocks have strips I'l of metal vulcanized to their upper faces and Acountersunk screws I8 extend through the plates I5 and into the strips Il. Before these screws are tightened, the upper faces of the strips II lie spaced below the lower surface of the plate I5, so that when the screws I8 are tightened, the blocks I5 are placed under tension. This tighto ening of the screws I 8 brings the plate I5 into a corporation of Penn- 1938, serial Nt. 198,675

engagement with the upper surfaces of the heads I4, so that such heads act as spacers between the plates 9 and I5. With the plate I5 held in this manner, it is clamped down against the bolt heads I 4, but at the same time, has some freedom of horizontal movement in its own plane due to the use of the rubber tension blocks. As a result, the plate I5 has freedom of expansion and contraction under temperature changes induced bythe polishing action oi the runners upon the glass sheet carried by the plate I5, and the tendency of the plate I5 to warp is, therefore, much less than if this plate were held against movement in its own plane.

Mounted on the edges of the plate 9 are the four flange members I9, such ange members being clamped in position by the bolts 20. These flange members carry the pegs 2| which act as stops for the side edges of the glass plate carried by the table. The four edges of the plate I5 are spaced away from the inner sides of the flange members i9, as indicated in Fig. 4, and these spaces are closed by means of strips of rubber 22 which are vulcanized on one side to the side of the flange member i9 and on the other side to the edge of the plate I5. The space 23 between the plates 9 and I5 is thus securely sealed off from the outside and at the same time the plate I5 is free to expand laterally, as heretofore pointed out. The space 23 between the two plates is designed to receive a cooling uid, such as water, so that the top plate I5 is maintained at a lower temperature than would otherwise be the case and the tendency of such plate to warp under temperature changes is, therefore, reduced. Water may be supplied to the space 23 through the pipe 24 (Fig. 3) having the fitting 25 at its end for connection with a supply pipe, the space being filled when the table reaches the entrance end of the polishing system. After the table has passed the polishing system, the Water may be Withdrawn from the space 23. It will be understood in this connection that any suitable means may be employed for supplying the space 23 with a cooling uid.

Fig. 5 illustrates a modication, in which the top plate 26 is spaced from the bottom plate 21 by means of the members 29 which are cup shaped in cross section and have threaded stems 29 engaging the plate 2l. In this case, the rubber tension blocks 35 are vulcanized at their lowei` sides to the members 28 and carry at their upper sides the strips 3| which are vulcanized to the upper faces of the tension blocks. As in the con.- struction of Figs. 1 to 4, the strips 3| normally lie with their upper faces spaced below the lower Aface of the plate 26, so that when the screws 32 are tightened, the blocks are placed under tension. The plate is thus free to expand laterally in its own plane, the rubber tension blocks permitting such movement, but at the same time the plate 26 is held very securely against the spacing members 28. The edges of the plate 26 are in this construction sealed by means of the rubber strips 33 and 34 which arevulcanized on their lower sides to the strips 35 and on their upper sides to the lowerl face of the plate 25. The strips35 are secured in position by means of the p bolts 36, the holes in the plate 26 through Which the bolts are` inserted being accessible through openings 31 which are subsequently filled with plugs. In this arrangement, the pegs 38 extend through the plates 26 and 2l. It will be apparent that the rubber strips 33 and 34 act as Vseals for the space between the plates 26 andg'i and at the same time permit the plate 25 to expand and contract freely.

Fig. 6 illustrates another modification in which the sleeves 39 act as spacers between the plates 4D and 4 l, such sleeves being clamped to the plate 40 by means of the bolts 42. The lower side of the plate 4l carries the sleeves 43 secured in position by the bolts 44. In this. case; the tension blocks are the rubber members 45, which are vulcanized to the sides of the sleeves 39 and 43, the arrangement being such that when the bolts 44 are tightened, and the plate 4I is pulled down against the ends of the spacers 39, the blocks 45 are placed under tension. As in the first form of construction, the seal between the flangesl 46 and the edge of the'plate 4I are rubber strips 41 vulcanized to the inner sides of the flanges 46 and to the edge of the plate 4l.

What I claim is: 1. A plate glass surfacing table comprising a 'Y metal body portion withra flat rectangular upper face, a false top for the table comprising a metal plate above said face,V positive spacing members distributed over said face and bearing against the lo-Wer surface of said plate for supporting it in parallel with said face, rubber tension blocks between said face and plate having one of their sides anchored with respect to said face, and

means carried by the plate for applying tension.

ried by the plate at each block for applying tenn sion thereto so that the plate is pulled yieldingly against the adjacent spacing members. f v

3. A plate glass surfacing table comprising a metal body portion with a flat rectangular kupper face, a false top for the table comp-rising a metal plate above said face, Apositive spacing members distributed over said face and bearing lagainst the lower surface of said plate for supporting it in parallel with said face, rubber tension blocks between said face and plate having one of their sides anchored with respect to said face, means carried by the plate for applying tension to the blocks so that the plate is pulled yieldingly against the spacing members, and rubber sealing strips for the space between said face and said plate,

distributed over said face and bearing against the lower surface of said plate for supporting it in parallel with said face, rubber tension blocks between said face and plate with one of their sides anchored with respect to said face, means carried by the plate for applying tension to the blocks so that the plate is pulled yieldingly against the spacing members, flanges projecting upward from said face at its four edges and secured thereto, said flanges having their upper faces ush with the upper face of the false top and having their inner sides spaced away from the edges of the false top, and rubber strips lling the spaces between the sides of this flange and the edges of the false top and vulcanized thereto.

5. A plate glass surfacing table 'comprising a -metal body portion with a iiat rectangular upper face, a false top for the table comprising Va metal plate above said face, supporting members distributed over said face anchored thereto and carrying positive spacing members engaging the lower surface of the plate, rubber tension blocks on the supporting members having their lower sides vulcanized thereto, metal strips vulcanized to the upper sides of the rubber blocks, and screw means carried by the plate and engaging the strips for applying tension to the blocks so that the plate is pulled yieldingly against the spacing members.

6. A plate glass surfacing table comprising a metal body portion with a flat rectangular upper face, a false top for lthe table comprising a metal plate above said face, supporting members distributed over said face, headed bolts extending through the members into said body portion with their heads engaging the lower surface ofthe plate and acting as spacers, rubber tension blocks on the supporting members having their lower sides vulcanized thereto, metal strips vulcanized to the upper sides of the rubber blocks, and screw means carried by the plate and engaging the strips for applying tension to the blocks so that the plate is pulled yieldingly against the spacing members. f

7. A plate glass surfacing table comprising a metal body portion with a flat rectangular upper face, a false top for the table comprising a metal plate above said face, supporting members distributed over said face having threaded stems anchoring them to said body portion and provided with fianges engaging the lower face of the plate and acting as spacers, rubber tension blocks on the supporting members having their lower sides vulcanized thereto, metal strips vulcanized to the'upper sides of the rubber blocks, and screw means carried by the plate and engaging the strips for applying tension to the blocks so that the plate is pulled yieldingly against the spacing members.

ALFRED L. I-IARRINGTON. 

